Reporting cell measurement results in a cellular communication system

ABSTRACT

The present invention relates to reporting cell measurement results associated with a plurality of cells of a cellular communication system. The reporting is transmitted from a station via a radio interface to receiver element of a cell serving the station. The cells are arranged in a reporting order that is to be used by the station for the reporting. The cell measurements are performed by the transceiver station for getting cell measurement results associated with a number of the cells. Relevant cell measurement results are then selected and the selected results are transmitted in the defined reporting order.

PRIORITY CLAIM

This is a national stage of PCT application No. PCT/EP00/09206, filed onSep. 19, 2000. Priority is claimed on that application, and on patentapplication No. 9922217.6 filed in Great Britain on Sep. 20, 1999.

FIELD OF THE INVENTION

The present invention relates to reporting in a cellular communicationsystem, and in particular, but not exclusively, to reporting ofmeasurement results from a transceiver station to the communicationsystem.

BACKGROUND OF THE INVENTION

A wireless communication network may comprise a cellular radio networkconsisting of cells. In most cases a cell can be defined as a certainarea covered by one or several base transceiver stations (BTS) servingmobile stations (MS) within the cell via a radio interface. The basestation may be connected to a base station subsystem (BSS). Severalcells may overlap and cover together a larger area, thereby forming thecoverage area of a cellular radio network. The cell (or group of cells)and thus the mobile station (MS) or similar user equipment (UE) withinone of the cells of the system can be controlled by a node providingcontroller functionality. Examples of the network controller include abase station controller (BSC), a radio network controller (RNC) and amobile switching center (MSC), but other control nodes may also be used.The controller can be connected further to a gateway or linking node,for example a gateway GPRS support node (GGSN) or gateway mobileswitching center (GMSC), linking the cell to the other parts of thecommunication system and/or other communication networks, such as to aPSTN (Public Switched Telecommunications Network) or to a data network,such as to a X.25 based network or to a TCP/IP (Transmission ControlProtocol/Internet Protocol) based network. The cellulartelecommunication networks typically operate in accordance with a givenstandard (or several standards) which sets out what the elements of thenetwork are permitted to do and how that should be achieved. Examples ofthe cellular telecommunications network standards include code divisionmultiple access (CDMA) based standards (such as the Digital AdvancedMobile Phone Service (DAMPS), or Wide-band CDMA or the proposedUniversal Mobile Telecommunications System (UMTS) or time divisionmultiple access (TDMA) based standards (such as GSM: Global Standard forMobile or the GSM based General Packet Radio Service (GPRS)) orfrequency division multiple access (FDMA) based standards. In additionto basic voice and data communication services, the users of the mobilestations are provided with various other services known to the skilledperson.

The mobile station and/or the base station may measure and/or defineseveral parameters concerning the conditions in the cell, such as signallevels (power) between the receiving and transmitting stations, qualityof the signal, distance between the stations, amount of transmitted dataand so on. The mobile station can be provided with appropriate means fordefining a value for any parameter that can be measured for theinteraction between the mobile station and any of the base stations orthe conditions in a cell. The measurements or definitions performed bythe mobile station will be referred to in the following as cellmeasurements and the results obtained by the mobile station will becorrespondingly referred to as cell measurement results.

During an ongoing call the mobile station may report to the networkcontroller so called neighbouring cell measurement results associatedwith cells neighbouring the cell serving the mobile station at thecurrent moment by a measurement result message. In other words, theneighbouring cells can be defined to be the other cells of the systemthan the cell currently serving the mobile station. For example, in theGSM based systems the reporting may be done on SACCH (Slow AssociatedControl Channel). In this instance the measurement result messageconsists of information related to the serving cell and also informationconcerning the six strongest neighbouring cells. In the GSM basedsystems the report message frame includes information bits for themeasured RX-level (received signal level), BCCH-frequency (BroadcastControl Channel frequency) and the BSIC (Base Station Identity Code) foreach reported neighbouring cell. At the current GSM based systems theRX-level is reported with six bits. The value range of the informationis set to be from −47 dBm to −10 dBm with 1 dB steps.

In the current measurement reports it is possible to report only sixneighbouring cells in maximum. Since the number of the cells with whichthe mobile station may interact can be greater than this it could beadvantageous to have a report covering more than only the six cells.This is especially the case in multisystem or multiband networks and/orin cellular communication systems operating in a multilayer environment.In general, the multimode systems can be defined as a communicationenvironment in which the mobile station may be in a such service areawhere it may be served by more than one serving network or system orstandard or frequency and so on. An example of a multiband system is adual-band GSM mobile stations served by both 900 MHz and 1800 MHzfrequencies. An example of a multisystem is a dual mode telephoneoperating e.g. in GSM networks and in UMTS networks.

For example, in the current GSM standard a reported neighbouring cellwill reserve 17 bits from the reporting message. There is no free spacein the current measurement report message to include more cellmeasurement results for the neighbouring cells than said measurementresults for six neighbouring cells.

In addition, the reporting of the RX-level with 6 bits only may causelimitations in the reporting range in some applications. Especially, themaximum value of the indicated RX-level may be insufficient for allapplications. Therefore it could be advantageous to be able to indicateRX-levels that are higher than the currently possible levels, such asthe −47 dBm maximum value. Reports of higher received signal levels isneeded e.g. for the purposes of handover decisions in instances wherethe mobile station is close to a sectored base station and moving fromone sector to another sector of the base station.

Furthermore, at signal levels above e.g. −47 dBm value, the currentmeasurement report cannot indicate if the serving cell has a higherpower than one of the neighbouring cells unless the serving cell isincluded in a list of the neighbouring cells. This approach is, however,not a desired solution since the number of the real neighbouring cellsreported to the network would go down from 6 to 5.

SUMMARY OF THE INVENTION

It is an aim of the embodiments of the present invention to address oneor several of the above problems.

According to one aspect of the present invention, there is provided amethod in a cellular communication system for reporting cell measurementresults associated with cells of the system from a transceiver stationvia a radio interface between the transceiver station and a cell servingthe transceiver station, comprising:

defining a reporting order of the cells to be used by the transceiverstation for reporting;

performing cell measurements at the transceiver station for getting cellmeasurement results associated with at least some of the cells;

selecting relevant cell measurement results from the performed cellmeasurements; and

reporting the cell measurement results from the transceiver station inthe defined reporting order.

According to another aspect of the present invention there is provided acellular communication system comprising:

a transceiver station;

a cell serving the transceiver station via a radio interface;

a plurality of further cells;

wherein the transceiver station comprises control means for performingcell measurements concerning at least some of the further cells, controlmeans for defining a reporting order of the measurement results, controlmeans for selecting relevant cell measurement results from the performedcell measurements, and control means for generating a report messagereporting the cell measurement results in the defined reporting order.

According to another aspect of the present invention there is provided amobile station for use in a cellular communication system comprisingcontrol means for performing cell measurements concerning cells of thesystem, control means for defining a reporting order of the measurementresults, control means for selecting relevant cell measurement resultsfrom the performed cell measurements, and control means for generating areport message reporting the cell measurement results in the definedreporting order.

According to another aspect of the present invention there is provided anetwork node of a cellular communication system comprising means forreceiving cell measurement results from a station communicating with oneof the cells of the system, said measurement results being associatedwith a plurality of cells of the communication system and being reportedfrom the station in a reporting order of the cells defined by thestation, control means for defining the reporting order used by thestation for the reporting and control means for attaching measurementresults to cells based on the reporting order.

According to more specific embodiments, the measurement results arereported by information symbol strings containing a plurality ofinformation symbols, wherein an indication symbol is included into themeasurement report string for indicating whether the followingpredefined number of symbols in the string includes the cell measurementresults of a subsequent cell in the reporting order of the cells orwhether the subsequent cell will not be reported in the measurementreport string. In addition, predefined information about the cells tothe measured may be received at the mobile station, wherein thedefinition of the reporting order is based on said received information.The reported measurement results may be associated with respective cellsat a control node of the cellular communication system.

The embodiments of the invention provide several advantages. By means ofsome of the embodiments it is possible to include cell measurementreports for a greater number of cells within a reporting message withoutincreasing the length of the reporting message string. Some of theembodiments enable use of a greater number of information symbols foreach of the reported cells without increasing the length of thereporting message or reducing the number of the cells reported by asingle message. By means of this it is possible to increase the range ofthe reported measurements. In addition, in some embodiments it is notnecessary to transmit an identification of the cell, such as informationof the frequency of the broadcast channel and the base station identity,for each of the measured cells together with the results from the mobilestation.

BRIEF DESCRIPTION OF DRAWINGS

For better understanding of the present invention, reference will now bemade by way of example to the accompanying drawings in which:

FIG. 1 shows a cellular radio system with which the embodiments of thepresent invention can be used;

FIG. 2 is a schematic presentation of a mobile station constructed inaccordance with the present invention;

FIG. 3 is a flowchart illustrating the operation of one embodiment ofthe present invention; and

FIG. 4 illustrates one example of coding of a report message inaccordance with one embodiment of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Reference is made to FIG. 1 which shows a cellular system with which theembodiments of the present invention can be used. It is noted that eventhough the exemplifying telecommunications network shown and describedin more detail in the following uses the terminology of a circuitswitched GSM (Global System for Mobile communications) public landmobile network (PLMN), the proposed solution may be used in any cellularcommunication system. It should also be appreciated that the embodimentsof the invention may be implemented using any number of cells. The radiocoverage area of a cell may consist, for example, of a relativelyomnidirectional pattern or a sector of a base station may be providedwith a directional or sector antenna (not shown). The sector basestation may use e.g. three 120° directional antennas whereby three radiocoverage areas are provided, or four 90° directional antennas providingfour radio coverage areas and so on, or any combinations of differentradio coverage beam widths. It should also be appreciated that basestations may sometimes be referred to as node B (e.g. in the UMTSstandard).

FIG. 1 illustrates two layers or cells 1 and 2, respectively. Thearrangement may be, for example, such that the first layer of cells 1belongs to a network based on a first standard and the second layer ofcells 2 belongs to a network based on a second standard. Each of twoeach cell 1,2 is served by the respective base transceiver station BTS.Each base transceiver station BTS is arranged to transmit signals to andreceive signals from the mobile station MS 7 in the cell. Likewise, themobile station is able to transmit signals to and receive signals fromthe respective base transceiver station. The mobile station 7accomplishes this via wireless or radio communication with the basestations. Typically a number of mobile stations will be communicationwith each base station although only one mobile station is shown in FIG.1 for clarity.

Each of the base stations is connected to a network controller, which inone form of the exemplifying GSM system comprises a base stationcontroller (BSC) 8 connected further to a Mobile Switching Center (MSC)9. In the described embodiment the BSC is providing the networkcontroller functionality for the purposes of the described embodiments.However, it is noted that the base station controller 8 controlling oneor several base stations between the network controller and the basestations may be omitted in some embodiments. Therefore any otherappropriate network element may be used for providing a controllerfunctionality than can be used for processing measurement informationfrom the mobile station 7. It is also noted that typically more than onenetwork controller is provided in a network. The network controller isconnected to other elements or parts of the telecommunications networksystem via a suitable linking or gateway apparatus, such as GatewayMobile Switching Center (GMSC; not shown).

The implementation of the communication between the mobile station, thebase station and the controller is known, and will thus not be discussedin more detail herein. It is sufficient to note that the interface maycomprise channels in both uplink and downlink directions between themobile station in the cell associated with a given base station and thatthe information sent to the mobile station and the data may be sent inany suitable format. The messages sent from the mobile stations mayinclude information identifying the mobile station (for instance, MS IDand/or IMSI (mobile Station Identity and/or International MobileSubscriber Identity, respectively)).

As disclosed by FIG. 1, the mobile station can be simultaneously in thesignaling area of several cells. The mobile station is arranged toperform measurements, for example in order to be able to provideinformation based on which a suitable cell can be selected for servingthe mobile station. In other words, in addition to controlling theongoing connection with the servicing base station, the mobile stationmay perform measurements concerning the other cells as well.

It should be appreciated that this description uses the termneighbouring cell for defining any further cell that can be reached by amobile station in a cell of the cellular communication system. That is,the cells need not to have any “border line” therebetween but theneighbouring cells or other cells may be partially overlapping, or evencovering the entire coverage area of the servicing cell. In addition,the neighbouring cells may be cells of another type of communicationnetwork (e.g. networks based on different standards) or cells of asystem using another frequency. The latter is the case when, forexample, so called dual-band mobile stations are used.

FIG. 3 illustrates a flow chart for an embodiment for transmittingreport messages from the mobile station. In the embodiment only suchmeasurement results that associate to relevant neighbouring cells arereported to the network controller. According to a preferred embodimentthis is accomplished without including any identification parameters ofthe related neighbour cells. The measurement results, such as RX-levels,are reported in a specific order of which the appropriate networkcontroller, such as the BSC or RNC, is also made aware of.

Since the controller is aware of the reporting order, it is possible forit to conclude to which neighbouring cells the reported measurementresults relate. Appropriate control or processing means 6 of thecontroller 8 of FIG. 1 for accomplishing this are known, and will thusnot be explained in more detail. It is sufficient to note that thecontroller nose is arranged to receive the cell measurement results fromthe mobile station 7 and to define measurement result and cell pairsbased on the reporting order such that a respective measurement resultsis associated with a respective cell.

According to one possibility the reporting order is defined in theprotocols and/or standards used by the cellular communication system.According to another approach the mobile station provides the controllerwith information of the reporting rules for setting the cells in anorder the mobile station is going to use when reporting the cellmeasurement results, e.g. the RX-levels of the respective base stationsto the network. According to a further possibility the controllerprovides the mobile station with instructions concerning the reportingorder to be used when reporting the cell measurement results. The mobilestation may also receive an elsewhere prepared reporting order, andthereafter use the received order as such for the reporting. In thiscase the definition processing done by the mobile station is fordefining that the received reporting order is to be used for thereporting. It is noted that the rules for setting the cells in order maybe changed during the operation of the communication system. The changemay be dynamic, e.g. the change may occur as response to a predefinedevent (e.g. a system failure, overload, peak hour conditions, night timeconditions, and so on) detected or defined by the system.

This explicit reporting order of the neighbouring cells may be definedby the mobile station based on neighbouring cell BCCH (Broadcast ControlChannel) frequencies (e.g. based on ARFCN: Absolute Radio FrequencyChannel Number) and the BSICs (Base Transceiver Station Identity Code)of the neighbouring cells received at the mobile station from thenetwork. As mentioned above, the appropriate controller in the radionetwork side is also aware of this reporting order of the cells. Themobile station proceeds the cell measurements and selects relevantneighbouring cell measurement results among the performed measurements.These selected relevant results are then transmitted to the network inthe known reporting order. The controller defined based on the knownreporting order those cells the respective reported results relate.

The selection of the relevant cells may be based on any appropriatepredefined rule of selection. The rules may be defined in the standardsthe mobile station and/or the communication system is arranged to use.The rules may be stored permanently in the mobile station. According toone possibility the rules are stored in an appropriate network elementand transmitted therefrom to the mobile station when ever required. Aswas the case with the rules for setting the cell in a predefined order,the rules for selecting relevant cells may also be changed when this isdeemed necessary. The selection of the relevant cells may be based, withno limitation to the following, on the measured signaling levels, usedradio frequencies, direction of the movement of the mobile station,loading conditions of the neighbouring cells and so on.

FIG. 2 illustrates schematically a sectioned mobile station 7 which maybe used in the embodiments of the invention. The mobile transceiverstation comprises an antenna 20 for receiving and transmitting radiosignals. The mobile station 7 comprises further control means 22 forperforming various cell measurements associated with several basestations. In addition, control means 24 are provided for generating thereporting order of the measurement results. Control means 26 areprovided for selecting the relevant ones of the performed cellmeasurements results. Control means 28 are provided for generating areport message reporting the relevant cell measurement results in thegenerated reporting order via the radio interface with the serving basestation. It should be appreciated that the functions of the controllers22 to 28 can be implemented by a single controller, or by two or threecontrollers or that said functions can be distributed to more than thefour control units 22 to 28 of the mobile station 7.

A preferred embodiment for the transmission of the measurement resultswill now be described with reference to FIG. 4, wherein specificindication bits are used in the report messages transmitted from themobile station to the network. More precisely, an indication bit can beused for each neighbouring cell measurement result indicating whetherthe following bit is a first bit of a relevant measurement result for acell or a bit indicating a next neighbouring cell in the predefinedreporting order. The latter may be the case e.g. when no measurementinformation is available for the preceding neighbouring cell andtherefore the cell does not have any relevancy for the operation of themobile station. However, the division between the relevant andnon-relevant cells may be based in any other criteria as well. The bitindicating a non-relevant cell can be referred to as a skip bit.

From FIG. 4 it can be seen that the measured RX-level is reported forthe cells which are in the reporting order list on places 1 to 5, 24 to29 and 32. No cell measurement result information is reported for theneighbouring cells being in the places 6 to 24 and 30 to 31 in thereporting order.

According to one possibility, the order of the bits for measurementresults and the indication bits is such that the first bits of themeasurement report string indicate only what cells are reported. Thefollowing bits will then include the information of the results. E.g. inthe exemplifying system of enabling 32 neighbouring cell, the first 32bit may be arranged such that the “1” indicates that the cell isreported. “0” would then indicate that the cell is not reported. Afterthe first 32 bits, the following information bits or other informationsymbols in the string inform in the reporting order the results forthose cells that were indicated by “1”.

Since the cells to which the cell measurement results relate can beidentified by the reporting order used in the measurement report, noadditional bits are required for the cell identification. Therefore moreneighbouring cells can be added to the measurement report. For example,if the number of bits reserved for a cell to be reported is seven bits,this is ten bits less than the number of bits reserved by the currentsolution in the GSM for reporting one neighbour cell. As thenon-relevant neighbouring cells are also included in the reporting orderof the measurement results, the non-relevant cells have to be indicatedin the measurement report. However, the number of bits reserved for anon-relevant neighbouring cell (i.e. not reported cell) may be only onebit, as will be explained later on in this specification.

According to a more specific example of the embodiment, the network maytransmit the neighbouring cell BCCH frequencies (e.g. the ARFCN values)in System Information 5 (SI 5), System Information 5bis and SystemInformation 5ter messages based on GSM Specification 04.18 version8.0.0. The BSICs of the neighbouring cells are transmitted to the mobilestation in a message indicating the identity of the transmittingstation. This may be a new message or then a message encapsulated toanother message which the mobile station may receive. According to oneoption the identity indication message replaces the SI 5 messages andcontains both the BCCH frequencies as well as the BSICs.

According to an embodiment the mobile station sets all the neighbouringcells in an explicit reporting order based on the above described twoparameters. The reporting order is also known by the network. It isnoted that each BCCH frequency may have more than one associated BSIC.After the above information has been received, each of the neighbouringcells can be identified with a unique BSIC/BCCH ARFCN pair and theneighbouring cells can be put into an explicit order according to thedata in the relevant system information messages.

The total number of neighbouring cells can be limited to correspond themobile station measurement capabilities. According to an embodiment thenumber of cells is 32, which is the maximum number of neighbouring cellsat the current network architectures. However, this is only an example,and the number of neighbouring cells can be smaller or greater than 32.

In the measurement report the RX-levels of the relevant neighbouringcells are reported using this specific order. The measurement reportincludes an indication bit for each neighbouring cell. By the indicationbit it may be indicated whether the following bits (for example, thefollowing 6 bits) describe the RX-level of that specific neighbouringcell or not. For example, the arrangement may be such that an indicationbit value “1” means that the RX-level is included and an indication bitvalue “0” means that no RX-level is not included for the given cell. Ifno RX-level is available the bit followed the current indication bitwill then be the indication bit for the next neighbouring cell in thereporting order.

The embodiments of the invention enable an arrangement where it is notnecessary to associate a BSIC and an index to each individualmeasurement result, thereby saving a lot of space in the report message.The BSIC is not required since the BSIC/BCCH frequency information istransmitted to the mobile station and the mobile station may decidewhich measurements are valid i.e. relevant and such which need to bereported. In the current systems this is done at the base stationcontroller. The index is not required and can thus be removed from thereport. The mapping of the RX-level or any other measurement result tothe corresponding cell is based on the order of the results instead ofany indexes.

Since the embodiment makes it possible with to leave the BSIC andBCCH-frequency of each neighbour cell out from the measurement reportmessage and thereby enables inclusion of measurement results (e.g. thereceived signal level) of a greater number of neighbour cells. Thereport includes only the RX-level of the reported neighbour cells andthe indication bit, an no other parameters are required to identify thecells in the report message. In the GSM example described above thismeans that since 107 bits reserved for neighbour cell measurementresults can be used so that only seven bits are used for a cell withmeasurement result and one bit is used for a cell without any (or with anon-relevant) measurement result. For example, all cells can be reportedin a cell having 32 neighbours such that the report includes measurementresults for seven neighbouring cells (12×7+20×1=104 bits). This leaveseven 3 bits free for other reporting purposes.

According to a measurement report message that is based on the GSMstandards, there can be 13 octets and 3 additional bits available forneighbouring cell reporting, thereby providing 8×13+3=107 bits longreporting string or frame. At the current systems one cell can have amaximum of 32 neighbouring cells. The RX-level reporting reserves sevenbits for a relevant neighbouring cell and one bit for a non-relevantneighbouring cell. In the case all neighbouring cells can be measured,the 15 first neighbouring cells on the list can be reported. If nolimitations is set to the placing of the cells in the reporting orderlist, the maximum number of cells would be 12. In this instance thenumber of the reported neighbouring cells can be doubled from the aboveby means of the embodiments of the present invention.

The reported signal levels may be indicated with relation to a certainpredefined reference signal level. The reference signal level may betransmitted in the same measurement report message. The reference signallevel is preferably set so that each of the relevant signal levels canbe reported by means of the reference level. More precisely, a referencelevel for the signal level is transmitted e.g. with three bits, with 4dB steps (for example, 0=−110 dBm, 1=−106 dBm, 2=−102 dBm). Eachmeasured signal level from the serving cell and from the relevantneighbouring cells are then indicated in the report in relation to thisreference signal level. The reference signal level may be chosen so thateach reported signal level is explicitly stronger or weaker than thereference signal level.

The following is presented in order to further clarify the scaling ofthe frame. The reference signal level may be indicated with three bits,thereby offering eight different values. Six bits are reserved for theindication of the relation between the measured result and the referencevalue. This makes it possible to have up to 63 dB dynamics in the signallevel reporting. If the difference from the reference level is indicatedwith five bits, then dynamic would be up to 31 dB, which may also besufficient for several applications. The five bit indication would saveone further bit per reported neighbouring cell when compared to thereceived signal level reporting used in some of the current cellularsystems.

Using reference level and indicating the difference from this referencelevel it is possible to widen the reporting range from −48 dBm tostronger signal levels. The stronger (i.e higher or greater) signallevels are levels >−48 dBm, such as −47 dBm, −40 dBm or −30 dBm.

The enhanced cell measurement reporting discussed above can be readilysupported by “new” mobiles stations comprising the required controlhardware and/or software, as illustrated by FIG. 2. It is, however,preferred that the embodiment are used under control of an appropriatenetwork element or elements. This guarantees compatibility between the“new” mobiles stations supporting the embodiments of the invention and“old” network implementations that cannot handle the described newreporting mode. If the neighbouring cell frequencies are sent withcurrent system information messages while the BSIC information is sentin separate messages, the mobile station may send measurement reportswith the “old” report after a handover until the mobile station isordered to use the new report mode, e.g. as a result of receiving themessage indicating the BSICs. By means of this it is possible tominimize the gap in neighbouring cell reporting after a handover, sincethe information of neighbouring cell frequencies can be received beforethe full information required for the new reporting format. The oldreporting format needs to be used until it is known that the new cellsupports the new reporting format. Alternatively the reporting modeafter the handover is controlled by a corresponding new indicator in thehandover command.

It should be appreciated that whilst embodiments of the presentinvention have been described in relation to mobile stations,embodiments of the present invention are applicable to any othersuitable type of user equipment. In addition, while a message containinginformation bits and an indication bit are discussed above, theembodiments may be implemented by using any appropriate informationsymbols.

It is also noted herein that while the above describes exemplifyingembodiments of the invention, there are several variations andmodifications which may be made to the disclosed solution withoutdeparting from the scope of the present invention as defined in theappended claims.

1. A method in a cellular communication system for reporting cellmeasurement results associated with cells of the system from atransceiver station via a radio interface between the transceiverstation and a cell serving the transceiver station, comprising: defininga reporting sequence of the cells to be used by the transceiver stationfor reporting; performing cell measurements at the transceiver stationfor getting cell measurement results associated with at least some ofthe cells; selecting relevant cell measurement results from theperformed cell measurements; and reporting the cell measurement resultsfrom the transceiver station in the defined reporting sequence withoutincluding any identification parameters of the cells.
 2. A methodaccording to claim 1, wherein the measurement results are reported byinformation symbol strings containing a plurality of informationsymbols, the method further comprising a step of including an indicationsymbol into the measurement report string for indicating whether thefollowing predefined number of symbols in the string includes the cellmeasurement results of a subsequent cell in the reporting sequence ofthe cells or whether the subsequent cell will not be reported in themeasurement report string.
 3. A method according to claim 2, wherein, inthe event that the cell measurement indication symbol indicates that itwill not be followed by symbols reporting the measurement results, thefollowing symbol included in the measurement report string is a furtherindication symbol designated for a cell following the subsequent cell inthe reporting sequence of the cells.
 4. A method according to claim 1,comprising further steps of receiving predefined information about thecells to be measured at the mobile station, and defining the reportingsequence based on said received information.
 5. A method according toclaim 4, wherein said information comprises frequency of a broadcastingcontrol channel and the identity of a transmitting base station of thecell to be measured.
 6. A method according to claim 4, wherein at leastpart of the information is transmitted in a separate message via thebroadcasting control channel.
 7. A method according to claim 1, furthercomprising a step of associating each of the reported measurementresults with respective cells at a control node of the cellularcommunication system.
 8. A method according to claim 1, wherein thereported cell measurement result for a cell comprises signal level of aradio signal received at the transceiver station.
 9. A method accordingto claim 1, wherein the reporting sequence is defined and the cellmeasurements are performed at the transceiver station for cells otherthan the serving cell.
 10. A method according to claim 1, wherein thereporting sequence is based on the information received from the servingcell.
 11. A method according to claim 1, wherein rules for defining thereporting sequence are stored at the transceiver station.
 12. A methodaccording to claim 1, comprising a step of transmitting rules for thereporting sequence to the transceiver station via the radio interface.13. A method according to claim 1, comprising a step of changing rulesfor defining the reporting sequence.
 14. A method according to claim 1,wherein rules for selecting the relevant other cells are stored at thetransceiver station.
 15. A method according to claim 1, comprising astep of transmitting rules for the selection of relevant cells to thetransceiver station via the radio interface.
 16. A method according toclaim 1, comprising a step of changing the rules for the selection ofthe relevant cells.
 17. A method according to claim 1, wherein thetransceiver station sends the communication system information of therules used for generating the cell measurement report.
 18. A methodaccording to claim 1, wherein the reported information of the cellmeasurement results is based on reference values.
 19. A method accordingto claim 18 in conjunction with claim 8, wherein the reportedinformation indicates if the measured signal level is stronger or weakerthan the reference value.
 20. A cellular communication systemcomprising: a transceiver station; a cell serving the transceiverstation via a radio interface; a plurality of further cells; wherein thetransceiver station comprises control means for performing cellmeasurements concerning at least some of the further cells, controlmeans for defining a reporting sequence of the measurement results,control means for selecting relevant cell measurement results from theperformed cell measurements, and control means for generating a reportmessage reporting the cell measurement results in the defined reportingsequence without including any identification parameters of the cells.21. A cellular communication system according to claim 20, comprising atleast two different cellular network arrangements.
 22. A cellularcommunication system according to claim 20, wherein the report messagecontains information symbols and at least one indication symbol in astring, said indication symbol indicating whether the followingpredefined number of symbols in the string define the cell measurementresults of a subsequent cell in the reporting sequence of the cells orwhether the subsequent cell will not be reported in the string.
 23. Acellular communication system according to claim 22, wherein, in theevent that the cell measurement indication symbol is for indicating thatit will not be followed by symbols reporting the measurement results,the following symbol in the measurement report string is a furtherindication symbol designated for a cell following the subsequent cell inthe reporting sequence of the cells.
 24. A cellular communication systemaccording to claim 20, wherein the transceiver station is arranged toreceive predefined information associated with at least some of thefurther cells for use in defining the reporting sequence of the furthercells.
 25. A cellular communication system according to claim 24,wherein the information comprises the frequency of a broadcastingcontrol channel and the identity of a transmitting base station of thecell to be measured.
 26. A cellular communication system according toclaim 20, further comprising a control node including means forassociating measurement results with corresponding cells based on thereporting sequence.
 27. A mobile station for use in a cellularcommunication system comprising control means for performing cellmeasurements concerning cells of the system, control means for defininga reporting sequence of the measurement results, control means forselecting relevant cell measurement results from the performed cellmeasurements, and control means for generating a report messagereporting the cell measurement results in the defined reporting sequencewithout including any identification parameters of the cells.
 28. Amobile station according to claim 27, said mobile station being arrangedto operate in at least two different cellular network systems.
 29. Amobile station according to claim 27 being further arranged to receivepredefined information associated with at least some of the furthercells for use in defining the reporting sequence of the further cells.30. A network node of a cellular communication system comprising meansfor receiving cell measurement results from a station communicating withone of the cells of the system, said measurement results beingassociated with a plurality of cells of the communication system andbeing reported from the station in a reporting sequence of the cellsdefined by the station, control means for defining the reporting orderused by the station for the reporting and control means for attachingmeasurement results to cells based on the reporting sequence withoutincluding any identification parameters of the cells.